package com.hmdp.utils;


import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * @ProjectName: hm-dianping
 * @PackageName: com.hmdp.utils
 * @Author: yunxi
 * @CreateTime: 2025-09-12  11:11
 * @Description:
 * @Version: 1.0
 */


public class MySimpleRedisLock implements ILock {

    private String name;
    private StringRedisTemplate stringRedisTemplate;

    public MySimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static{
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.Lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }


    @Override
    public boolean tryLock(long timeoutSec) {
        // 获取当前线程Id
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        // 获取锁
        Boolean success = stringRedisTemplate.opsForValue().
                setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock(){
        // 使用Redis调用lua脚本，一行代码保证“判断锁是否一致”和“释放锁”的原子性
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId()
        );
    }

//    @Override
//    public void unlock() {
//        // 获取线程标识
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//        // 获取锁中的标识
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//        // 判断当前线程是不是当时拿到锁的线程
//        if (threadId.equals(id)) {
//            // 释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }

}
